pgsql: Tweak a comment to agree a bit better with the new dispensation

Log Message:
-----------
Tweak a comment to agree a bit better with the new dispensation that
locales are database-wide, not server-wide.

Modified Files:
--------------
pgsql/src/backend/commands:
dbcommands.c (r1.222 -> r1.223)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/dbcommands.c?r1=1.222&r2=1.223)